Post mounting arrangement

ABSTRACT

A post mounting arrangement for ground installation of a post comprising a tubular body portion ( 6 ) which is adapted to be installed into the ground and has an open end adapted to receive a post ( 2 ) to be supported. The open end of the tubular body portion comprises an enlarged flange portion defining a head portion ( 14 ) of the tubular main body portion ( 6 ). The head flange portion ( 14 ) includes a resilient retaining collar ( 12, 12 ′) adapted to receive and engage the post, and a strengthening band ( 8 ). The head portion ( 14 ) comprises a first recess ( 22 ) defined therein within which the said collar ( 12, 12 ′) is engaged and mounted, and a second recess ( 20 ) defined in the head portion adapted to receive the said strengthening band ( 8 ). The collar may comprise a shock absorbing element ( 12 ′) having a groove ( 42 ) capable of receiving an expansion ring ( 44 ) to lock the element into place and seal it both to the post ( 2 ) and the head portion ( 14 ). Alternatively, the head portion ( 14 ) further comprises a separate cap ( 10 ) which is adapted to be fitted to and engages with said head portion ( 14 ) to enclose said recesses ( 20, 22 ) and secure said collar ( 12 ) and strengthening ring ( 8 ) within said recesses.

The present invention relates to a post mounting arrangement for, inparticular, mounting and erecting items of street furniture for examplepedestrian guard rails, street signs or the like. Specifically thepresent invention relates to a socket arrangement for mounting andsecuring a post into the ground.

Throughout the road network and in our towns and cities there are avariety of situations where signs and barriers are present which fortheir support rely on the use of poles fixed into the ground. This typeof structure, by the very nature of its location, is very vulnerable toimpact from vehicular traffic and where poles enter the ground they arehighly susceptible to corrosion.

When an impact or severe corrosion occurs, the resultant damage normallynecessitates the need to remove the pole, or series of poles, andreplace it. As most poles are fixed into the ground in concrete, theirreplacement is time consuming, often involving shutting down sections ofroad or pavement with the associated inconvenience and the total cost isvery expensive. Firstly, this invention seeks to provide a pole housingthat can withstand the destructive impact to a pole without sustainingdamage and which will then permit rapid replacement of the damaged pole,hence significantly reducing the cost, time and inconvenience caused bythe construction work incurred in their replacement.

In any situation where there is an impact, the more energy that can beabsorbed within the structure without reaching the failure load of thecomponents, then the less will be the damage to the structures involved.In situations where the poles form part of a crash barrier or guard railsystem, it becomes a significant advantage if within the system thereare provided specific components which absorb impact energy.

The conventional method and arrangement for installing a post is to diga suitably sized hole at the installation site. The base of the post isplaced into this hole and the remainder of the hole surrounding the postis filled in with concrete. The concrete sets and the post is therebyrigidly and permanently retained in the ground.

A problem with this arrangement is that the post is permanently fixedinto the ground. Should the post become damaged (for example by beinghit by a vehicle, etc.) and need to be replaced, the concrete needs tobe broken up and removed. A new post then needs to be fitted and freshconcrete poured into the hole and allowed to set to fix the new post.This can take a considerable amount of time and can be difficult.

Alternative arrangements have been proposed, and are described in WO92/20889 and WO 96/02704. In these arrangement a separate socket,comprising a tubular sleeve, is installed into the ground. The base ofthe post is then installed into the sleeve. A retaining portion, forexample a resilient collar, of the sleeve releasably secures the postwithin the sleeve and so to the ground by virtue of an interference fitand frictional engagement of the post and sleeve. The sleeve istypically made from a plastics material such that it is resistance tocorrosion. In order to strengthen the sleeve, in particular at the upperend where in use the bending stresses are at their greatest the sleevemay include a strengthening ring embedded and formed into the sleeve.

With such an arrangement the post can be more easily replaced in theevent of damage by extracting the post from the socket/sleeve, andinserting a new post into the socket sleeve, without the need to dig upthe ground surrounding the installation site. A problem with such anarrangement however is that the post can also be undesirably removed forexample by vandals extracting the post from the socket. Whilstincreasing the interference fit between the socket and post can makeremoval by vandals more difficult it will also inherently with thisarrangement make removal, and installation of the post within the socketby authorised users replacing the post, more difficult.

Also in some cases when the post, or street furniture, is damaged forexample following impact by a vehicle, the socket and in particular theembedded strengthening ring can be damaged. In such a case if thestrengthening ring is damaged the socket needs to be removed andreplaced by digging up the ground and breaking up the concrete withinwhich the sleeve is affixed in a similar manner to that withconventional direct fixing and concreting in of the post. This obviatesthe advantages of the sleeve/socket arrangement.

The manufacture of an embedded strengthening ring within the mouldedplastic sleeve/socket is also difficult and problematic. Thisundesirably increases costs.

It is therefore desirable to provide an improved post mountingarrangement for ground installation of a post which addresses the abovedescribed problems and/or which offers improvements generally. Theinvention seeks to provide a pole housing which is capable of absorbingimpact energy, the amount of which can be tailored to some extent tomatch the specific application of the housing, and which is easilyreplaceable by authorised persons.

According to the present invention there is provided a post mountingarrangement and method of erecting a post as set out in the accompanyingclaims.

In an embodiment of the invention there is provided a post mountingarrangement for ground installation of a post comprising a tubular bodyportion which is adapted to be installed into the ground and has an openend adapted to receive a post to be supported. The open end of thetubular body portion comprises an enlarged flange portion defining ahead portion of the tubular main body portion. The head flange portionincludes a resilient retaining collar adapted to receive and engage thepost, and a strengthening band. The head portion comprises a firstrecess defined therein within which the said collar is engaged andmounted, and a second recess defined in the head portion outwardly ofsaid first recess and adapted to receive the said strengthening band.The head portion further comprises a separate cap which is adapted to befitted to and engages with said head portion to enclose said recessesand secure said collar and strengthening ring within said recesses.

With such an arrangement, and the securing of the collar by the separatecap, the collar can be arranged to more securely grip the post toprevent unauthorised removal of the post whilst the post can be easilyremoved, when required by removal of the cap to release the collar.Furthermore by locating the collar and strengthening band in the saidrecesses and then securing them in place using a separate cap, thestrengthening band and collar of the assembly can be disassembled andthe strengthening band and collar individually replaced in the event ofdamage without having to remove the entire socket from the ground. Theuse of a separate cap, collar and in particular strengthening bandlocated in the socket and secured in the socket by the cap, is alsoeasier (and cheaper) to fabricate than some of the prior proposals inwhich these components are integrally fabricated and/or embedded withinthe socket assembly.

The cap when engaged and fitted to the head portion is preferablyadapted to urge the collar inwards, in use, into engagement with thepost. Furthermore said first recess defined in said head portion ispreferably adapted such that said collar can flex away from, in use,engagement with said post. The cap accordingly includes a portion whichis adapted, when said cap is fitted to said head portion, cooperateswith said first recess to urge said collar, in use, into engagement withsaid post. The cap in particular may include a flange projection whichcooperates with said first recess and head portion when the cap isfitted and in use urge the collar into engagement with said post.

Such an arrangement provides for a more secure gripping and securing ofthe post within the tubular main body and socket.

Preferably the collar comprises a post abutment surface which is adaptedto provide, in use, an enhanced interference fit and grip on the saidpost against movement in a first direction as compared to movement in asecond direction. The post abutment surface of said collar may comprisesat least one serration or ridge. The at least one serration ispreferably directionally orientated such that a first surface of saidserration abuts said post and a different angle to a second surface ofsaid serration.

Such an arrangement for the abutment surface of the collar allows thepost to be more easily inserted into the collar than be removed from thecollar.

The collar is preferably fabricated from a resilient material, forexample a rubber material. The tubular body portion is preferablyfabricated from an injection moulded plastic material, for examplenylon.

The cap is preferably adapted to be snap fitted to said head portion. Inparticular the cap may include a flange lip which is cooperativelyengaged with a cooperating flange lip on said head portion.

In an alternative construction, the cap may be dispensed with. Thecollar is replaced with a shock absorber element which, in use, coversthe whole of the top of the head portion (apart where the shaft of thepole passes through). It is preferably held in place by the insertion ofan expansion ring into a groove in the element thereby expanding it andcausing it to grip the pole and seal against both the pole and the headportion. In this embodiment the pole is clamped by friction betweenitself, the collar and the head portion. Moreover, the collar sealsagainst ingress of water into the body thus help reduce or preventcorrosion of the pole.

A further advantage of this construction is that the collar (element)and strengthening ring can be formed as a “cartridge” (with the elementholding or partly encapsulating the ring) which can be inserted andremoved as a unit very easily.

The reinforcing ring on its outer face is a close fit with the upperpart of the main body. An impact on the pole is first transmitted to theshock absorber element which is then supported by the reinforcing ring,which in turn spreads the load into the main body and concretefoundation. The reinforcing ring is designed to be stronger than thepole which can catastrophically fail before any damage can occur to themain body. If damage occurred to the shock absorber element and/or thereinforcing ring, then these can effectively be replaced as a singlecartridge.

The groove is preferably a circumferential groove which will accept a“C” shaped expansion ring. When a pole is placed into the post mountingarrangement, the expansion ring is driven into the groove. The ringexpands the top of the shock absorber element so that the inner surfaceis clamped and sealed to the pole, gripping and retaining the pole. Theouter face is thrust tightly to and sealed against the very top edge ofthe main body. The internal top edge of the main body may be providedwith a reverse flange or lip which locates into a groove in the outerface of the shock absorber. Once the expansion ring is located in thegroove, extreme force would be needed to separate the shock absorberfrom the main body.

The post and tubular main body portion may be of a generally circular,square or other cross section.

The present invention will now be described by way of example only withreference to the following figures in which:

FIG. 1 is a cross sectional view through the post mounting arrangementand socket in accordance with an embodiment of the present invention;

FIG. 2 is a more detailed cross sectional view of the head portion ofthe socket shown in FIG. 1;

FIG. 3 is a cross-sectional view of the tubular main body;

FIG. 4 is a similar view to FIG. 1 of another embodiment;

FIG. 5 is a plan view of a compliant shock absorber;

FIG. 6 a cross sectional view on line x—x of FIG. 5;

FIG. 7 is a similar view to FIG. 1 of another embodiment;

FIG. 8 is a similar view to FIG. 2 of the embodiment of FIG. 7; and

FIG. 9 is a plan view of the embodiment of FIG. 7.

Referring to FIGS. 1 and 2, there is shown a post mounting arrangementfor mounting and securing a post (2) within the ground (1). The post (2)is associated with an item of street furniture, for example a trafficsign post, pedestrian guard rail leg post or mounting post for someother form of street furniture. It will be appreciated that there is awide range of street furniture which is secured to the ground by way ofone or more such mounting posts (2). Where a number of posts are to besecured, for example to mount a pedestrian guard rail fence, a series ofsuch mounting arrangements can be disposed in the ground and along thestreet in order to secure a series of posts.

The post mounting arrangement comprises a post mounting socket assembly(4) which in use is installed within the ground (1) with a head portion(14) of the socket (4) generally flush with the ground level and theremainder of the socket (4) buried into the ground (1). A base end of apost (2) is fitted and secured into this socket (4) thereby securing andmounting the post (2) in the ground (1).

The socket assembly (4) comprises a main generally tubular main bodyportion (6). The tubular main body (6) defines an internal bore whichcorresponds to, although is slightly larger than, the outside diameterof the post (2) such that the post (2), in use can be easily insertedinto the inner bore of the main body (6). In this embodiment the mainbody portion (6) is generally square and the post (2) is similarly of asquare shape. It will be appreciated though that the main body (6) andpost (2) could have other cross sectional shapes, for examplecylindrical or rectangular in other embodiments.

Projecting from the outside of the main body portion (6) and spacedcircumferentially around the outer circumference are a number oflongitudinal ribs (5). Longitudinally spaced along the main body (6)there are also further circumferential ribs (16) which similarly projectfrom the outside of the main tubular body (6). These ribs (5,16)strengthen the main tubular body (6). Also, when installed into theground (1), the ribs (5,16) are held and engaged in the surroundingground material surrounding the outside of the socket (4). This ensuresthat the mounting socket (4), when installed into the ground (1), issecurely affixed into the ground (1) and restrained from twisting and/orbeing withdrawn vertically from the ground (1).

One end, the in use lower end, of the tubular main body (6) is closedoff in order to prevent the ingress of ground material into the insideof the tubular main body (6) and also to provide an end stop for thebase end of the post (2) when installed within the tubular main body(6). The closed end (17) of the main tubular body (6) comprises anupright stud projection (18) which projects longitudinally into the boreof the tubular main body (6). This stud projection (18) is concentricwith the bore of the main tubular body (6) and is spaced radially fromthe inside of the bore. The side wall of the stud (18) is sloped andtapered inwardly with respect to the bore as the stud (18) projects intothe bore. The base end of the post (2) is generally hollow and in usewhen the post (2) is fitted into the socket (4) the stud (18) engagesthe inside of the hollow base end of the tubular post (2). The taperingof the side wall of the stud (18) is configured such that there is aprogressive interference fit and frictional engagement between the studand post as the post is inserted vertically into the socket and onto thestud (18). The engagement of the stud with the post (2) locates and, inpart secures the post (2) by friction into the socket (4).

The other open end of the tubular main body (6) and socket (4) comprisesan enlarged head portion (14) in the form of an enlarged flange (15)projecting from and concentric with the main tubular body portion (6)and having an outer diameter greater than that of the main tubular bodyportion (6). This enlarged head portion (14) is shown in greater detailin FIG. 2.

Defined within the head portion (14) there is a first annular recess(22) concentric with the bore of the main tubular body (6). This recess(22) opens out inwardly onto the bore and in effect comprises a largerdiameter bore portion of the bore of the main tubular body (6), andchannel/groove, within the flange (14). An annular collar (12) is fittedand located within this first recess (22).

The annular collar (12) is fabricated from a resilient material, forexample a rubber material such as for example EPDM (Ethylene PropyleneDiene Monomer) a synthetic rubber. The inner diameter of the collar (12)is such that an inner surface of the collar tightly abuts against theouter surface of the installed post (2) such that there is a tightinterference fit between the collar (12) and post (2). The annularcollar (12), which itself is secured within the socket (4), grips andengages the outside of the post (2) thereby retaining and securing thepost 2 within the socket (4). The inner surface (30) of the collar (12)includes a series of longitudinally spaced serrated circumferentialridges or teeth (31 a,31 b,31 c) which project inwardly. The serrations(31 a,31 b,31 c) are arranged and profiled such that they and the collar(12) provide greater resistance to longitudinal movement of the post (2)out of the socket (4) (i.e. upward) than to movement of the post (2)into the socket (i.e. downward). As shown, for example, in FIG. 2 theserrations (31 a,31 b,31 c) have a triangular cross section and arearranged in a fir tree type arrangement in which an upper part of eachserration (31 a,31 b,31 c) is at a shallower tapering angle to the post(2) outer surface as compared to a lower portion of the each serration(31 a,31 b,31 c). In this way the post (2) can be more easily installedinto the socket (4) whilst removal of the post (2) from the socket (4),for example by a vandal, is made more difficult. In effect the collar(12) with the serrations (31 a,31 b,31 c) provides a one way directionalgrip and enhanced interference fit upon the post(2). It will beappreciated though that other profiling of the collar (12) instead ofthe serrations (31 a,31 b,31 c) illustrated could be used to providethis function in other embodiments.

Outwardly of the first recess (22) a second annular recess (20), in theform of a channel/groove formed in the end surface of the head portion(14), is defined within the head portion (14). The second recess (20) issimilarly concentric with the bore of the main tubular body (6), and thefirst recess (22). This second recess (20) is radially separated fromthe first recess by a dividing wall portion (21) of the flange headportion (14). A strengthening band (8) in the form of an annular ring islocated and fitted into the second recess (20). This strengthening orreinforcing band (8) is typically made from a material which is strongerthan that of the remainder of the socket (4). Whilst the socket (4)could be fabricated from an injection moulded plastic material, forexample a thermoplastic such a polypropylene, the strengthening band (8)could comprise 40% glass fibre reinforced compression moulded nylonmaterial could be used for the strengthening band (8). The strengtheningband (8) by virtue of its greater strength and also due to itscontinuous circumferential configuration, strengthens the upper regionof the socket(4).

Upon the longitudinal distil end of the head flange portion (14) thereis a cap (10).

Once fitted the cap (10) closes off the upper longitudinal ends of thefirst and second recesses (22,20). The cap (10) is arranged to securethe strengthening band (8) and collar (12) within the recesses (22,20),and ensure that they are properly engaged therein. The cap, when fittedto the socket (4), thereby prevents the strengthening band (8) andcollar (12) from moving longitudinally (vertically upwards as shown)from and out of the socket (4).

The cap (10) comprises a generally planar disc member with a centralhole defined therein. The central hole within the cap (10) generallycorresponds to the outer diameter of the post (2) such that the post (2)can be fitted through the central hole in the cap (10) and into the boreof the socket (4). The cap (10) is arranged to securely engage and befitted to the head portion (14). In this embodiment a peripheral flangewall (25) depends from the periphery of the cap (10). Around the distalend of this peripheral flange (25) there is an inwardly direct lipprojection (24). This flange and lip (24) are arranged to be engagedagainst a cooperating outward lip projection (26) on the outer surfaceof the head portion (14). During assembly the cap (10) is ‘snap-fitted’onto the head portion (14). The cap (10) is pressed longitudinally ontothe end of the flange head portion (14). The lip (24) on the peripheralflange (25) of the cap (10) rides over and longitudinally beyond the lip(26) on the outside of the head portion (14) with the peripheral flange(25) of the cap (10) flexing outwardly slightly to allow this. Theengagement of the two cooperating lip projections (24,26) then securesthe cap (10) onto the end of the head portion (14). To remove the cap(10), for example to remove the post (2), the flange (25) of the cap(10) has to be prised outwards, using for example a screwdriver or othersuitable tool, to allow the lip (24) to be eased back over the lip (26)on the head portion (14).

It will be appreciated that other alternative arrangements could be usedto secure the cap (10) to the head portion (14). In particular, forexample, fastening screws which are engaged within the head portion (14)could be used instead of or in addition to the snap fit arrangement. Theuse of fastening screws would provide a more secure engagement of thecap with the head portion although would add complexity to thearrangement. To prevent unauthorised removal the heads of the fasteningscrews could have a non standard shape such that a specific ‘key’ toolis required for the screws.

The dividing wall portion (21) of the head portion (14) between thefirst and second recesses (22,20), terminates short of the end of thelongitudinal end of the head portion (14) and part way along the collar(12) and strengthening band (8). The cap (10) includes a further annularflange wall (28) projecting longitudinally from the cap (10). Thisflange wall (28), when the cap (10) is fitted to the head portion (14)fits, and is engaged, between the upper portion of the collar (12) andstrengthening band (8) and continues the dividing wall portion (21) ofthe head portion (14). The fitting of the flange wall (28) between thecollar (12) and strengthening band (8) when the cap (10) is fittedsecures the upper portions of the strengthening band (8) and collar (12)radially in position within the socket assembly (4). This secures andfurther locks the strengthening band collar in position within thesocket (4). In particular this also urges the collar (12) radially andincreases the frictional engagement of the post (2) and collar (12)thereby increasing the grip on the post (2).

In use the socket (4) is seated at the bottom of a hole excavated in theground (1) and concrete (or other filling material) is poured into thehole around the socket (4) and allowed to set to hold the socket (4) inplace in the ground (1). The head portion (14) of the socket (4) ispositioned substantially level with the ground level. The strengtheningband (8) and collar (12) are then fitted into the respective recesses inthe socket (4). Alternatively the strengthening band (8) and/or collar(12) may have already been fitted into the recesses (22,20) prior toinstallation of the socket (4) in the ground (1). The cap (10) is thenfitted over the base of the post (2) with the post (2) passing thoughthe central hole in the cap (10). The base of the post (2) is theninserted into and through the collar (12) and into the bore of thesocket (4). The profiling and directional engagement of the serrations(31 a,31 b,31 c) on the collar (12) mean that this insertion of the post(2) is relatively easy with the base of the post relatively easilypassing through the collar (12). Furthermore, since the upper portion ofthe collar (12) is not restrained by the dividing wall (21), the upperpart of the collar (12) can deflect outwards such that is not urged intoengagement with the post (2) so further allowing easy insertion of thepost (2) through the collar (12). The post (2) is inserted into thesocket (4) until the base of the post (2) is engaged upon the stud (18)at the bottom end of the socket (4). With the post (2) installed withinthe socket (4), the cap (10) is then slid longitudinally down the post(2) and onto the end of the head portion (14) of the socket (4). The cap(10) is then pressed home and snap fitted onto the end of the headportion (14) of the socket (4). The cap (10) thereby secures and ensuresthat the strengthening band (8) and collar (12) are engaged within therecesses (20,22) and into the head portion (14) of the socket (4). Theflange (28) of the cap (10), as the cap (10) is fitted, fits and isinserted between the upper part of the collar (12) and strengtheningband (8). As the cap (10) is fitted this urges and presses the collar(12) inwards and further into engagement with the post (2). In this waythe cap (10) secures and engages the collar (12) in place and within thesocket (4) and thereby secures the post within the socket (4). The capin effect when fitted, and by its engagement with the head portion (14)locks the strengthening band (8) and collar (12) in position within thesocket (4) and the collar (12) into engagement with the post (2) tothereby secure the post (2) within the socket (4).

To remove the post (2), for example in the event of damage to the post(2) or street furniture which it mounts, the cap (10) is first prisedway from and off the head portion (14) of the socket (4). The cap (10)can then be slid longitudinally upwards, away from and out of engagementwith the socket(4). This releases the collar (12) from engagement withinthe head portion (14), opening the upper end of the recesses (20,22) andallowing the upper portion of the collar (12) to expand and/or moveradially outwards. This unlocks the collar (12) (and also strengtheningband (8) from engagement within the socket (4) and partially fromengagement with the post (2). The post (2) is thereby at least partiallyreleased from the socket (4) and can be withdrawn from the socket (4).As the post (2) is withdrawn the post (2) either slides out from thecollar (12) and/or the collar (12) slides out of the recess (22) in thesocket (4) along with the post (2). In the later situation the collarcan then separately be removed (if necessary by cutting) from the post(2).

Subsequently the original post (2), or a replacement post (2), may bereinstalled and inserted into the original socket (4) in a similarmanner to that described above. If necessary a new collar (12) can beused and fitted into the socket (4). In this way the mounting posts aresecurely fixed into the ground (1) whilst they can be removed andreplaced simply and easily without necessitating extensive digging andbreaking up of the ground.

It will also be appreciated that with this arrangement the post (2) canbe more securely locked in place by engagement of the separate cap (10)with the socket (4). In particular, tighter gripping collars can be usedwithout adversely preventing authorised disassembly and removal of thepost. Consequently removal of the post (2) by vandals casually pullingon the post (2) is substantially prevented, whilst the post (2) can beeasily removed by suitably equipped personnel first removing the cap(10) to release the post (2) and collar (12) from the socket (4).

The use of a removable separate cap to secure and lock the collar (12)into the socket (4), also allows the use of a directionally engaged andgripping collar (12) which more securely and tightly grips the post (2)from removal than against insertion of the post. The use of such adirectional gripping collar (12) is problematic with conventionalarrangements since it makes authorised removal similarly difficult.

Additionally, by using a separate cap (10) which locks and urges thecollar into further engagement with the post also further improves thegripping of the post whilst again not adversely affecting authorisedremoval of the post.

A further advantage of this arrangement is that the collar,strengthening band, and cap can all be individually replaced in theevent of damage. If for example the post or street furniture which itmounts is hit be a vehicle a high impact load is applied to the headportion (14) of the socket (4) with the post (2) typically pivotingabout the head (14) of the socket (2) about which the post (2) ismounted into the ground. In particular this impact load is most likelyto cause the strengthening band (8), which reinforces the head portion(14) to fracture. With previous arrangements, the fracture or damage ofthe strengthening band or reinforcement embedded within the socket (4)would necessitate digging up of the ground and removal and of the entiresocket (4). In contrast with this arrangement, the main socket (4) canbe left in place and the strengthening band simply replaced within therecess (20). Similarly, if the cap (10) or collar is damaged they canalso be individually and easily replaced.

A yet further advantage of this arrangement is that it is considerablyeasier to fabricate than the prior arrangements. The socket (4) and capis preferably made from injection moulded plastic. The strengtheningband (8) and collar (12) are then installed as separate items within thefinished moulded socket. It will be appreciated that the moulding of thesocket without an embedded strengthening band (8) is considerably morestraightforward than, as with the prior arrangements, having to mouldthe socket with an embedded band (8). Separate materials, optimised forthe individual parts can also more readily be used since the variousparts (socket body, strengthening band (8), collar (12) and cap (10))are separate and discrete parts. For example, in the describedembodiment the main tubular body (6) and main part of the socket aremade from injection moulded polypropylene. This is easy to injectionmould. The strengthening band (8) is made from 40% glass (either glassfibre or glass) reinforced compression moulded nylon to provide goodstrength. The collar is made from a EPDM, a synthetic rubber, to providehigh frictional engagement and also a degree of resilience to securelygrip the post. It will be appreciated though that other suitablematerials and comminations of materials could be used in otherembodiments.

Referring now to FIG. 3, the tubes used in a typical application aremanufactured to generous tolerances and to provide a means foraccommodating these variations the bore of the tubular main body portion(6) has been provided with a number (dependant on tube cross sectionalshape of the tube) of longitudinal ridges (33), reference FIG. 3 (whichis a cross sectional view of the tubular main body (6) suitable toreceive a square section tube). The peaks of the ridges (33) representthe minimum size of the tube and if a slightly larger tube is fitted,then as it is forced into the tubular main body (6) it shaves therequired amount off the peak of the ridges (33) to create a hole ofdimensions that correspond to that particular tube. In variations of thepole housing that require higher levels of shock absorbency, thisfeature may be omitted.

In the original design, when the pole (2) is subjected to an impact thecollar (12), which is made of a compliant material, is deformed to somedegree and as this occurs energy is absorbed. The absorption of energyreduces the peak load applied to the pole by the impact and will eitherreduce the damage to the pole or could prevent structural failure of thepole.

To provide a degree of shock absorption it is necessary to allow thecomponent being subjected to an impact to move a distance whilstsimultaneously providing a resistance to the impact. This is based onthe theory that work done is equal to force multiplied by distancetravelled. In the case of the pole housing, the pole, when subjected toan impact, should be allowed to move whilst generating a force resistingthat movement. Ideally, the optimum force produced should be onlyslightly less that the force necessary to cause failure of the pole.

Referring now to FIGS. 4–6, the head portion (14) essentially remains aspreviously described with the exception that the pole (2) is allowed tomove more within the collar (12) to increase the amount of shockabsorption. In the base of the main tubular body (6) a compliant bush(34) is housed and retained in position by a cap (36) which is a snapfit into the base of the main tubular body (6). The pole (2) is a slidefit into the compliant bush (6) which firmly locates pole (2). The bush(34) has a chamfer (35) to aid location and retention of the pole. Inthe event of an impact to the pole (2), the bush (6) and collar (12)permit the pole to move whilst providing a considerable resistance tothe movement and hence absorbing the impact load. The compliant bush(34) can have the force it produces to resist the impact load modifiedby varying the properties of the compliant material, such as hardness,and by changing the cross sectional profile. FIGS. 5 and 6 showcompliant bush (34) with grooves (37) around the periphery. These havethe effect of reducing the resistance to the impact. Differentapplications will employ tubes of different strengths and it isimportant to be able to adjust the properties of both the collar (12)and compliant bush (34) to achieve maximum shock absorption. The bush isreplaceable.

Referring now to FIGS. 7–9, a further, and currently preferred,embodiment of the invention will be described using like numerals forlike parts. The principal change in this embodiment is that the cap (10)is dispensed with and the collar (12) is replaced with a shock absorbingelement (12′) of a similar resilient material, such as an elastomer(EPDM). It has inclined top surfaces (40) to shed water away from thepole (2). Incorporated into the inclined top surface (40) is acircumferential groove (42) capable of accepting an expansion ring (44),typically made of a plastics material such as nylon. The expansion ring(44) is “C”-shaped, and has a split (46) (FIG. 9). This enables it tohave one end inserted into the groove (42) and for the remainder of thering then to be progressively forced into the groove. This arrangementpermits higher insertion forces to be generated and also permits a toolto be inserted into the split (46) to remove the ring when necessary.The cross-sectional shape of the expansion ring (44) is generally wedgeshaped (46) to aid penetration into the groove and to exert expansionforces on it. In order that the expansion ring (44) may be retained onceinserted into the groove (42), its top edges (48) taper at a steeperangle than the wedge shape (46), thus acting to retain the ring in thegroove.

As can be seen from FIG. 9, only a small part of the expansion ring (44)is visible from the top of the head portion and a special insertion toolis required to achieve removal. It is thus not obvious how the pole (2)is retained in the mounting arrangement and this, combined with the needfor a special tool, makes it difficult for vandals to remove the pole(2).

The strengthening band (8) in this embodiment is retained in the recess(20), and passing through the bore of the strengthening band (8) is aliner sleeve (50) which is an extension of the shock absorber element(12′). The lower end of the liner sleeve (50) is provided with a lip(52) which retains the two components together, and when combined withthe strengthening band (8) the two form a “cartridge” enabling them tobe inserted and removed as a single unit.

The top of the collar (12′) interlocks with the top of the head portion(14) by means of a groove (54) in the collar and corresponding lip (56)of the top of the head portion (14).

In use, the “cartridge” comprising the collar (12′) and strengtheningband (8) (but without the expansion ring (44) in place) is slipped overthe pole (2) and the pole inserted into the bore (6). As before, thebase of the pole locates by means of a chamfer (35) into the bush (34).The cartridge is pushed downwardly until the collar (12′) locates on topof the head portion (14) with the lip (56) engaging in the groove (54).The expansion ring (44) is then forced into the circumferential groove(42), causing the top of the collar (12′) to expand and press againstboth the post (2) and the top of the wall of the head portion (14). Thetightness achieved by the insertion of the expansion ring (44) creates aseal and locks the shock absorber element (12′) to both the main bodyportion (14) and the post (2). If, as shown in FIG. 9, the outer face ofthe main body is square, then when the shock absorber element (12′) islocked into place by the expansion ring it is not possible to rotate it.

The strengthening band (8) is typically made of a glass fibre reinforcednylon material and is a slide fit into its recess (20) in the tubularportion (6).

In situations where the pole (2) has received an impact sufficient tocause failure, the expansion ring (44) is removed and the pole (2) andcollar (12′)/strengthening band (8) “cartridge” can be removed from thetubular portion (6) which will not be damaged. It is then a simple taskto replace the pole (2) together with a new cartridge.

Whilst the above arrangement has been described with reference to asingle post mounting, it will be appreciated that the same principlescan be applied to a single double socket arrangement in which two postscan be mounted within the same socket assembly. In such a case, thesocket assembly would comprise two internal bore sections and twocollars (possibly joined into a single element). Similarly a singlemultiple post socket could also be produced.

1. A post mounting arrangement for ground installation of a post,comprising a tubular body portion which is adapted to be installed intothe ground and has an open end adapted to receive a post to besupported, the open end of the tubular body portion comprising anenlarged flange portion defining a head portion of the tubular main bodyportion, the head flange portion includes a resilient retaining collaradapted to receive and engage the post, and a strengthening band;wherein the head portion comprises a first recess defined therein withinwhich the said collar is engaged and mounted, a second recess defined inthe head portion adapted to receive the said strengthening band, and thewhole being adapted to be fitted to and engage with the post to enclosethe tubular body portion and secure the post and strengthening band, thecollar and band being removable.
 2. An arrangement as defined in claim1, wherein a cap is provided adapted to be fitted to and engage withsaid head portion to enclose the recesses and secure the collar andstrengthening band in place.
 3. A post mounting arrangement as claimedin claim 2 in which the cap when engaged and fitted to the head portionis adapted to urge the collar inwards, in use, into engagement with thepost.
 4. A post mounting arrangement as claimed in claim 2 in which saidcap includes a portion which is adapted, when said cap is fitted to saidhead portion, cooperates with said first recess to urge said collar, inuse into engagement with said post.
 5. A post mounting arrangement asclaimed in claim 4 in which said cap includes a flange projection whichcooperates with said first recess and head portion to when the cap isfitted and in use urge the collar into engagement with said post.
 6. Apost mounting arrangement as claimed in claim 2 in which the collarcomprises a post abutment surface which is adapted to provide, in use,an enhanced interference fit and grip on the said post against movementin a first direction as compared to movement in a second direction.
 7. Apost mounting arrangement as claimed in claim 6 in which said postabutment surface of said collar comprises at least one serration orridge.
 8. A post mounting arrangement as claimed in claim 7 in whichsaid at least one serrations is directionally orientated such that afirst surface of said serration abuts said post and a different angle toa second surface of said serration.
 9. A post mounting arrangement asclaimed in claim 2 in which said cap is adapted to be snap fitted tosaid head portion.
 10. A post mounting arrangement as claimed in claim 9in which said cap includes a flange lip which is cooperatively engagedwith a cooperating flange lip on said head portion.
 11. An arrangementas claimed in claim 1, wherein the collar comprises a shock absorberelement having a groove capable of receiving an expansion ring to lockthe element into place.
 12. An arrangement as claimed in claim 11,wherein the shock absorber element, in use, covers and seals the wholeof the top of the head portion.
 13. An arrangement as claimed in claim11, wherein the element interlocks with the top of the head portion. 14.An arrangement as claimed in claim 11, wherein the strengthening band isretained between the second recess and an extended sleeve portion of theelement.
 15. A post mounting arrangement as claimed in claim 1, in whichthe post and tubular main body portion are of a generally circular crosssection.
 16. A post mounting arrangement as claimed in claim 1 in whichthe post and tubular main body portion are of a generally square orrectangular cross section.
 17. A post mounting arrangement as claimed inclaim 1 in which said first recess defined in said head portion isadapted such that said collar can flex away from, in use, engagementwith said post.
 18. A post mounting arrangement as claimed in claim 1 inwhich the collar is fabricated from a resilient material.
 19. A postmounting arrangement as claimed in claim 18 in which said collar isfabricated from a rubber material.
 20. A post mounting arrangement asclaimed in claim 1 in which said tubular body portion is fabricated froman injection moulded plastic material.
 21. A post mounting arrangementas claimed in claim 20 in which said plastic material comprisespolypropylene.
 22. A Method of erecting a post using a post mountingarrangement as claimed in claim 1, comprising the steps of: installingsaid tubular main body in the ground, installing said strengthening bandin said second recess, installing said collar in said first recess,inserting a base end of said post through said collar and into saidtubular body portion, and fitting said cap to said head portion tosecure said collar within said head portion, or inserting said expansionring into the shock absorbing element.
 23. A Method of erecting a postas claimed in claim 22 in which said post is inserted through saidcollar prior to installing said collar and inserting said post into saidmain tubular body.